A printer mechanism or printing apparatus may include one or more print cartridges.
Each print cartridge includes one or more ink ejecting orifice arrays and is associated with at least one particular type or color of ink. Users dismount and mount print cartridges for various reasons, e.g., to select a different type of ink, different ink color, or to remove and replace an empty print cartridge.
Accurate mechanical registration among the print cartridges and orifices carried thereby is needed to provide high print quality. Variation in relative position among the print cartridges and with respect to the print cartridge carriage can affect the final result, e.g., when the print cartridge position as mounted on the carriage varies the printer mechanism can lack accurate, known, registration between the print cartridges and the media.
Due to mechanical variation in print cartridge mounting on a print cartridge carriage, such registration does not always occur. A given printer mechanism and print cartridge carriage may be designed to suitably align, in both the horizontal (scan axis) direction and the vertical (media advance axis) direction, the orifices on different print cartridges. Variation, e.g., along the media axis, may occur, especially after a print cartridge has been mounted or dismounted.
Such vertical and horizontal offsets are typically considered when coordinating production of print imaging by ejecting ink droplets from one or more print cartridges. In addition, a printer mechanism can be further calibrated or aligned relative to non-spatial aspects of the printing mechanism, e.g., performance aspects such as energy use and mechanical aspects including carriage movement and bi-directional printing control.
Calibration or alignment can bring a printer mechanism closer to its intended level of print imaging quality.
Because such calibrations do not persist over time for a given printer mechanism, printer mechanisms often include calibration procedures and functions. Typically, once a set of print cartridges is mounted upon the print cartridge carriage and a suitable calibration is performed, re-calibration is not needed again until after a print cartridge is dismounted. Re-calibration may be performed, however, at any time. For example, a user detecting reduced quality in print imaging can initiate a re-calibration procedure by suitably interacting with a printer mechanism or computer or computer network attached thereto. Generally, calibration is performed when a print cartridge is mounted as such event gives rise to opportunity for a change, for example, in relative cartridge-to-cartridge and in relative cartridge-to-carriage registration.
A user could be asked to perform complex or burdensome calibration tasks, but as a practical matter the limits of user tolerance and ability fall short of a complete spectrum of the calibration tasks needed to bring a particular printer mechanism to a desired performance level. Also, users as a population typically cannot consistently interpret and judge calibration marks, and therefore generally do not reliably produce consistent print imaging through a corresponding population of printer mechanisms through participation in a calibration procedure. As a result, “manual” methods of calibration are often simplified, with the adverse effect that the complexity and number of calibration parameters presented are often less than those desirably performed for best print imaging results.
Printing systems having “automatic” calibration and alignment methods that do not require such complex involvement from users generally are more expensive due to the additional components required to automate the calibration. Also, placing an optical sensor on a print cartridge carriage in implementation of an “automatic” method introduces significant challenge in producing accurate scanning data due to the rapid reciprocating or scanning motion of such carriage and hysteresis reflected therein.
For these and other reasons, there is a need for the present invention.